1. Field of the Invention
The present invention relates to a display and operation device, such as a mobile phone terminal, that displays an operation screen on a display panel of a display unit, and to an operation device, such as an infrared remote controller, that includes a key operation unit having a plurality of operation keys.
2. Description of the Related Art
In a device with multiple operation keys (buttons), such as a mobile phone terminal or an infrared remote controller for a TV set, all the operation keys or the operation keys of similar types are formed in the same size in rows and columns.
For example, Japanese Unexamined Patent Application Publication No. 2008-10281 describes a straight-type mobile phone terminal including a display unit and a key operation unit on a surface of its housing. In the straight-type mobile phone terminal, numeric keys in the key operation unit are formed in the same size in rows and columns.
Japanese Unexamined Patent Application Publication No. 2008-66997 describes a foldable mobile phone terminal including an upper housing with a display unit that can be opened and closed relative to a lower housing with a key operation unit. In the mobile phone terminal, dial keys in the key operation unit are formed in the same size in rows and columns.
Another type of existing device has a touch panel on the display panel of a display unit, such as a liquid crystal display. This type of device displays an operation screen on the display panel, thereby allowing a user to select a menu item or the like by touching an icon on the operation screen via the touch panel.
The device with the touch panel displays a plurality of icons in the same size in rows and columns on the operation screen as with the device with the operation keys.